What I would do is rename the folder back to the old one, create a new empty folder with the name you want, check iTunes can locate it correctly (the folder path to the music will need to be exactly the same), then go into iTunes>Preferences>Advanced and change the music folder location to the new one you created. Click OK, then in the Menu Bar go to File>Library>Consolidate Library and it will move everything into the new folder.

Next time you move your iTunes music folder around, you need to change the iTunes Music folder location and consolidate library to move it.

You might be able to just change the iTunes music folder location to the new folder, in fact try this first, but the method I outlined above will make sure all your music is in the right folder.